Transcend PC2-4200 DDR2 Overclocking Madness

Once again we test the limits of Transcend DDR2 533, this time in 1024MB (x2) module size. If you recall, overclocking DDR SDRAM resulted in higher frequencies when smaller 256MB modules were used. Fortunately DDR2 doesn?t seem to be bootstrapped in the same manner. Transcend memory has been keeping pace in performance with some of the more costly modules out there and for much less money. Their current DDR2-533MHz modules are based on Elipida E5108AE-5C-E IC?s and they?ve simply been spectacular.

Overclocking Old School

Transcend epitomizes a straight forward approach to memory offering a quality product without the unnecessary accoutrements. Transcend memory is some of the least expensive memory on the market and their DDR2 line offers next generation memory users a high performance product at a budget price. Today's review is a straight forward attempt to overclock Transcend's DDR2-533MHz in 1GB modules (TS128MLQ72V5J) on the Asus P5AD2-E Premium. I chose this 925XE based motherboard because those looking to purchase memory in this price-range are probably not going through $300 motherboards like Imelda Marcos goes through shoes.

Overclocking Old School

Advances made by Intel, albeit by necessity or design, have introduced numerous "safety" and "efficiency" features into their processors. Features such as On Demand, Thermal Monitor, Thermal Monitor 2, PROCHOT # Signal, and THERMTRIP # Signal, while advantageous for the life of the processor in many respects, may in fact be the bane of the Overclocker's existence. (see 90nm 6xx Datasheet (sec. 5.2.1 ~ 5.2.5.)) This is because most of the aforementioned features are antagonists to the types of effects overclocking produces, especially if vcore is to be raised. Fortunately my preferred method of overclocking is more conducive to what many may see as constraints put in place by the manufacturer. In recent articles I've been dividing the Art of Overclocking into two distinct schools. 1.) Extreme Overclocking; which involves overvolting and/or extreme cooling as a means to attain maximum clock speeds. 2.) Purist Overclocking; involving an intimate knowledge of manufacturing and the exploitation of manufacturing processes. This method is less dependent upon "pushing" the CPU to extremes and relies more on finding a diamond in the rough, as we have found in our Pentium 630.

Insofar as the Purist approach is concerned we rely on educating ourselves as to the design and manufacturing specifics of each processor as it leaves the Fab. In CPU production a single core design may have several innate features such as instruction-sets and/or high speed cache which are initially disabled in lower priced models. As speeds increase or the "model" maturates the chip-maker will begin enabling more cache and perhaps a dormant 64-bit instruction set (for example) with each consecutive feature demanding a higher price. The most common example is of course increasing locked multiplier values to determine each model's speed. One of Intel's most versatile processor cores (from a marketing standpoint) was the Socket-478 based, Pentium4 Northwood. Simply reading through Intel's datasheet on this CPU, Intel® Pentium® 4 Processor on 0.13 Micron Process Datasheet one could surmise their 2.4C may be a 3.4EE under the hood. Of course for the Enthusiast it's almost impossible to enable many of those features although there have been occurrences where Enthusiasts have accidentally discovered a specific attribute, in some cases it was unexpected for that core. For our purposes we'll employ the Purist approach since our 630 seems to be unlimited in its overclocking potential.

Overclocking Memory

Almost anything can be overclocked and there has even been overclocking articles on how to overclock an optical mouse, which entails increasing dpi for faster tracking. Overclocking memory is somewhat different from overclocking a CPU, or even a GPU, although insofar as the manufacturing process the basics are almost identical. In each case silicon ingots are grown, sliced, polished, undergo photolithography, etching, etc., however; CPU complexity and tolerances make them quite different when it comes to overclocking. Memory manufactured for such and such a speed have much tighter tolerances. If a given memory chip is intended to run at 533MHz at CL4-4-4-12 there's a possibility more headroom (speed) can be exacted, however; without increasing voltage (VDIMM) it's doubtful that memory will be able to maintain those timings at a higher speed. Some memory can be run slower with tighter timings which may not require voltage increase but then you sacrifice speed. There are of course some modules which perform exceptionally well at high speeds while concurrently maintaining tight timings. Winbond's infamous BH-5 was one such animal, not because it could overclock and retain tight timings without the need for increased voltage, in fact that's rare in semi-conductors. Winbond BH-5 did so well because they were able to consume large amounts of current which resulted in high speed mated with some of the tightest timings. Increasing voltage didn't do much for timings in our test today, however; our Elipida based modules did very well with very little voltage where frequency is concerned.

Cooling

Alphacool makes what I consider to be some of the very best watercooling hardware on the planet. They're not only ergonomical, cost-effective and CAD-crafted works of art, they out-perform most of what's available today. European Enthusiasts have had the pleasure of this German based H20 hardware for some time. None-the-less I've been lucky enough to have been testing Alphacool hardware and I'm most impressed. Cooling with H20 and the fact we have no need to raise vcore should effectively double the life of our Pentium 630.

Test System

CPU

P4 630 Retail

Mainboard

Asus P5AD2-E Premium

Memory

Transcend PC2-4200 1024MBx2

Graphics

Sapphire X800 XT PCI-e

Power Supply

PCPower&Cooling TurboCool 850SLI

Cooling

Alphacool NexXxos BOLD

Operating System

Windows XP SP2

Test System / Methodology

We'll use two 1024MB Transcend "heatspreaderless" modules (unmatched) in Dual Channel mode for the entirety of this test. My goal was simply to push the memory as far as it could go simultaneously holding the tightest timings possible. The Asus P5AD2-E Premium isn't the newest board out there, but as fast as Intel releases chipsets were probably representing the majority of Pentium owners. I had to sell my Canadian Quarter collection (of which I only had five) to get this P5AD2-E Premium and 630 together. Thank goodness there are still a few manufacturers willing to help out budding writers. I began by running the memory at it's rated speed of 533MHz which could have been achieved any number of ways for example using a memory divider (multiplier), however; I chose to overclock our Pentium 630 to 4027MHz from it's default speed of 3.0GHz. This translated to a FSB speed of 268FSB running our memory on a 1:1 ratio, or 534MHz. Latencies at this speed were easily maintained under the SPD or manually at CL4-4-4-11. VDIMM remained at 1.80V ~ 1.85V.

Our next thumbnail below exemplifies running the memory on SPD at the maximum frequency of 746MHz resulting in 5-5-5-15.

Our final thumbnail exemplifies the very best results attained during the tests being 746MHz at 4-4-4-11 with VDIMM 2.20V.

During the overclocking process I tried every conceivable voltage setting; including chipset, memory, FSB termination, and then every memory divider (multiplier) just about exhausting all BIOS options. Switching out Transcend for OCZ Gold PC2-6400 or DDR2-800 I was unable to surpass the 747MHz memory speed. This is indicative of a chipset or some other motherboard limitation. In the next section I've included benchmarks at 746MHz comparing both CL5-5-5-15 and 4-4-4-11. For those not wanting to raise VDIMM as high as 2.20V running under SPD or Auto at 746MHz and 1.85V VDIMM will result in CL5-5-5-15 timings.